I think a huge reason was because some places did not have certain animals. Other animals were to hard to domesticate, such as the elephant. In the documentary Guns, Germs, and Steel it shows the people trying to capture an elephant. They failed and never really domesticated the elephant. Later on in the documentary it shows people riding elephants. This doesn't mean that we have total control over them. They are still wild in heart.
The grizzly bear is a perfect example of modern attempts of domestication. Just like the elephants, they are still wild. If you see a bear in a circus doing tricks and you think that the human is in total control, in my opinion they really dont. In a way I think that they are like dogs. If you give them food, they will submit. If the bear feels threatened in any way, they will react in a violent way. A.K.A. show their "wild" side. Think of Siegfried and Roy.
The grizzly bear is a perfect example of modern attempts of domestication. Just like the elephants, they are still wild. If you see a bear in a circus doing tricks and you think that the human is in total control, in my opinion they really dont. In a way I think that they are like dogs. If you give them food, they will submit. If the bear feels threatened in any way, they will react in a violent way. A.K.A. show their "wild" side.